Data Domain: VTL Library Fails to VARY ON After Adding Additional Slots | iSeries | AS400

After increasing the number of slots in a Data Domain VTL library, IBM i fails to VARY ON the VTL library. The following error is reported:

Message ID: CPD2692  
Device TAPMLBLxx vary on failed. Reset required.

This issue can occur even if the VTL library was previously operational with fewer slots.

IBM i restricts the maximum number of storage elements (slots) per tape library based on the IBM i OS version, required PTF levels, and the tape library attachment type.

• IBM i versions prior to 7.2 support a maximum of 5000 slots by default.
• Support for larger libraries (up to 15000 slots) requires specific PTFs or is included in the base release with IBM i 7.2.
• If a VTL library exceeds the supported slot limit, IBM i fails to create or vary on the media library resource.

Required PTFs to enable support for up to 15000 slots:

• V6R1M1 – MF55406
• IBM i 7.1 – MF55409
• IBM i 7.2 – Supported in base release

If these requirements are not met, the slot limit remains at 5000.

1. VARY OFF the Data Domain VTL TAPMLB resource on the IBM i host.
2. Remove the changer and tape drives from the access group.
3. Perform an IPL of the Fibre Channel tape IOP/IOA.
   (Refer to page 95 of the PowerProtect DD Virtual Tape Library for IBM i Integration Guide.)
4. Clear failed and non-reporting tape resources in SST.
   (Refer to page 98 of the PowerProtect DD Virtual Tape Library for IBM i Integration Guide.)
5. Modify the VTL configuration to reduce the number of slots to within the supported limit.
6. Add the changer and tape drives back to the access group.
7. Rescan the tape library by VARY ON of the TAPMLB resource.

How to Verify the Number of Slots in Data Domain VTL

• Data Domain GUI:
  Navigate to Data Management → VTL → Virtual Tape Libraries → VTL Service → Libraries, then select the relevant library.
• Data Domain CLI:
  Run the following command:

  vtl show config